A control system to control an output regulator. The output regulator to convert an input voltage to a regulated output. The output regulator including a power stage to generate a power output from the input voltage and an output filter to filter the power output to generate the regulated output. A digital controller, responsive to a sense signal corresponding to the regulated output, to generate a drive signal to control the power stage. The digital controller including and selecting between at least three operating modes, a selected one of the operating modes to generate the drive signal